New Oil Cooler fitted - Should I Prime?

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New Oil Cooler fitted - Should I Prime?

Postby roj » Sun 16.11.2025, 16:56

Hi there,

I've just fitted a brand new oil cooler, pipes and washers. My question is, should I prime the rad completely full before reattaching and turning over/starting?

The internet has mixed results. Some people do, some don't.

Any thoughts or experience?

Cheers, Rog.
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Re: New Oil Cooler fitted - Should I Prime?

Postby RonR » Sun 16.11.2025, 22:30

When I did mine I filled it to 3/4 so there was enough oil to circulate around the circuit.
I didn't fancy the consequences of the oil system running dry!
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Re: New Oil Cooler fitted - Should I Prime?

Postby Tuga2112 » Mon 17.11.2025, 09:42

i cant remmebr what i did when i did mine.
most likely whatever Dave advised.

however if i was goign to do it today. i would probably install it dry, than fill up the normal way , trip the inertia switch and crank it and check level a few times. let it sit a hour or 2 and repeat.. minimum twice but probably more
from my experience with running a whole mile with the pipe burst. there seems to be enough residue in the engine to keep it alive for a short period without causing any harm.

cranking from the starter is a bit more convinient than taking out the spark plugs, raise the driver side and manually turn the engine.
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Re: New Oil Cooler fitted - Should I Prime?

Postby dapinky » Mon 17.11.2025, 11:44

I can't remember how I did mine - but, like Joao, if I had to think about it today, this is what I'd say....

... as there whole oil capacity of the sump is quite low (compared to many other cars), the quantity of oil in the cooler and filter is a fairly high percentage. I wouldn't want to suddenly (or gradually!) lose 1 Litre of oil whilst running the engine, as there may well be other places which are then starved of oil.

Obviously, we are not even thinking of revving the engine up to load anything, and it would be done at idle (or crank speed), which would cause little to no harm.

I think that I'd probably pour some into the new radiator, but not worry about it being full (if I could do it easily enough) - but if not, then I'd add the 'extra' quantity for the filter/cooler to the sump, then crank it on the starter (fuel cut-out operated), check the level, then when it is stable push the plunger on the fuel cut-out and fire it up.

Check for any leaks, then allow it to run for a short while.

Check level again, then run until hot enough for fans to kick in and out a few times - keep looking for drips. All done. Allow to cool, check for leaks caused by contraction of metalwork whilst cooling. Final level check, finished.

Of course, this is in a perfect world - I really don't think it would be a problem to just fire up the engine at idle, then turn it off, chuck some oil in to the level required, check for leaks and be on your way!!!
Dave

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...oh, and a 2006 Freelander destined for the jungles of The Gambia - 4500 miles across roads, desert and tracks - what could possibly go wrong?
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